Dr Jodi Richardson
GPS REVOLUTION! Sparked by the possibilities of global positioning satellites, technology is changing the game for coaches.
ICTURE this… you’re relaxing at home watching Geelong battle it out against Carlton at
the ‘G. Ablett intercepts a long bomb in the back pocket and tears down the wing with Judd chasing him. On your screen you can see that Ablett is accelerating and reaches a top speed of 30 kmh, just eluding Judd, who can manage a top speed of only 28 kmh. Meanwhile, you compare the heart rates of both players and the distance they have each run in the game to that point. This describes just a fraction of the broadcasting potential with the use of Global Positioning System (GPS) technology in Australian rules. GPS has been used in football for several years. Initially, the AFL restricted the number of players in a team to be fitted with GPS to five, and allowed monitoring for only 10 games per year. There is no longer any restriction and teams like Geelong and Brisbane Lions hook up every player at every game and training session. Adrian Faccioni, managing director of GPSports Systems, which supplies GPS systems to Geelong and Brisbane Lions, said the technology enabled coaching staff to accurately quantify playing and training loads, to ensure that players were training the way they played, and helped in the tailoring of training for each individual.
Faccioni said the device included a heart rate monitor and an accelerometer. It utilises the United States satellite system that surrounds the globe. When you turn the device on it picks up signals that are being sent from a small number of satellites to work out the precise position of each player. When the player moves, the device is able to calculate the distance and speed the player has moved. “The GPS is used in AFL to capture all of the positions, speeds and distances during a game or a training session,” said Faccioni. “We then combine this with their heart rate, which is a measure of the player’s physiological stress, and the accelerometer, which measures accelerations and decelerations to give us a measure of the musculoskeletal loading on a player. “We combine those three things (GPS, heart rate and body load) and then stream that data live to a laptop on the sidelines for club usage. “The data can also go directly to the broadcasters or can be sent to an iPhone so the coach or trainer can see the data live from anywhere that there is internet access – even from the other side of the world.” What is described here is just the tip of the iceberg with respect to the potential of this technology. Faccioni said his company used a team of experts including hardware, software and firmware engineers,
GOT HIM: Crow Brent Reilly wraps up Carlton’s Chris Judd. exercise physiologists, sports scientists, biomechanists and physiologists, all working together on research and development. “Though a few years away yet, we aim to be able to measure parameters such as player lactic acid, core temperature, glucose and pH,” he said. “Once you can combine all of those with the current technology, then you get a really amazing toy. “At the moment, we aren’t that far away from allowing the viewer, even in a stadium, to be able to log on to their own phone and see their favorite athlete’s performance stats while they are watching the game.” As with any technology, as new models are released to market, older models become less expensive. The same is true of these GPS devices. The SPI Pro X is the latest model to Inside Football
be released in March by GPSports at a cost of around $30,000 for 10 units. Clubs that fit out every player usually buy 50 units. This technology has no doubt revolutionised player monitoring in the AFL but as University of Technology Sydney academic and Essendon sports scientist Dr Aaron Coutts explains, it is an excellent tool, but the key is in the interpretation of the data. “We use GPS to measure what we have done but it doesn’t tell you how well you have done it,” Coutts said. “It is not a measure of football performance. It tells you how far you have run and how much of that running is high intensity. “It tells us if we are implementing training how we intend and it gives us an indication of the workload of players in games.”
Wednesday, March 17, 2010
Coutts said some players covered up to 17.5km in games and reached speeds of up to 35 kmh, but he stressed that running long distances and running fast did not mean that the players had necessarily played well. “More hard running doesn’t necessarily mean that you are performing better as a footballer,” he said. “Research in soccer shows us that teams that work the most are lower ranked. “To be more skillful allows you to work less, conserve energy and perform better as the match goes on. “That’s why you want mature players with good fundamental skills and technical knowledge and a good team game plan to make them efficient to run out games better. “In short, play hard and play smart. “AFL is probably the most demanding team sport so players need to be physically very prepared and technically proficient.” What Coutts finds most impressive about the data is seeing players who are running at a high intensity for large parts of the game. With multiple interchanges, players still need to be able to complete large volumes of high intensity running to be useful. “It’s an impressive effort from players running around 4km to 5km per game at high intensity; this is usually accomplished by our midfield players.” Though speeds of over 30 kmh are impressive, Coutts said that we would see faster speeds if players were sprinting for longer distances, but since AFL is predominantly a game of short
Inside the game 21 ‘The ball tracking enables a coach to … see that a full forward made, for example, 30 efforts, but contested the ball with 10 of those efforts and gained possession with five.’ sprints, we probably won’t see exactly what some players are capable of in terms of top speed. At Essendon, GPS data is just part of the decision making process for interchange on game day. A player may not be travelling far or fast but still be working very hard so ultimately that decision is made by the coach. Essendon finds the GPS data useful for determining whether training is mimicking match intensity, while the data is also useful to determine what an injured player has achieved in their rehabilitation training and compare how this relates to their previous performance. “There really is no limit to the application of this measurement tool, but the real skill is in knowing what information is useful and applying this information to your needs,” said Coutts. He and his colleagues have conducted academic research into the validity and reliability of GPS use in football. They concluded that data from different GPS devices should not be used interchangeably, which means that teams would be wise to always allocate the same GPS unit to a player. Other research examined running performance in the AFL. One of the most interesting conclusions was that players who work at higher intensity during a quarter have a greater reduction in intensity during the next quarter. This is important to know when considering interchange during a game. Annually since 2005, Ben Wisbey and his colleagues using GPS tracking have published a report examining the movement demands of hundreds of AFL footballers.
The most recent report, published in 2009, shows that on average an AFL player will cover around 12km per game with an average speed of 7 kmh and a top speed of around 30 kmh. A player will typically engage in some 240 moderate accelerations and 10 rapid accelerations. The report concludes that “nomadic or midfield players have greater physical demands than fixed forwards and defenders”. Originally, GPS technology focused on the physical demands of AFL football where emphasis was on data including indications of player fitness, effort and fatigue. Though this information is still integral to player monitoring and coaching decisions for clubs, the technology has now been extended to significantly contribute data to the tactical side of coaching. minimaxX technology and software developed by Catapult Innovations offers clubs all of the physical data on players but also allows the creation of 2D animations of player movement relative to the ball and the sporting field. Catapult Innovations works collaboratively with the Australian Institute of Sport and is the major supplier of GPS technology to AFL clubs. CEO Shaun Holthouse said that clubs both in Australia and overseas were very interested in this technology as video footage did not provide a full picture. “The reason the clubs are interested is that the video footage is typically ball centric, focused on movement of the ball so you can see what is happening with the ball and a few metres around,” Holthouse said.
“From a coaching point of view, what you are really interested in is how the rest of your team is structured outside of that narrow bit of vision and how they are preparing for the next passage of play. “You can’t get that from video. Even sometimes when you do have footage that covers the whole ground, it is often not a clear representation of what clubs are interested in, which is space, movement and team structure.” The 2D animation is simplified and very easy to follow as players are represented by a dot around a jumper number. The software also allows for generation of “hotspot plots”, which show where a player has spent his time on the field. White traces can be generated on the on-screen field to show the movement of players and multi-coloured traces can be generated for players, where each colour represents a different speed. This data is available wirelessly and in real time. This way coaching staff can access the data during the match. Alternatively, it can be viewed after the game or training session for analysis. You may be beginning to wonder how much more this technology can advance Aussie rules, but the innovation doesn’t stop there. Catapult has teamed up with Sherrin to create the “SmartBall”, which integrates an “e-tag” inside the football, which is then detected by nearby minimaxX devices worn by players. Since the ball is near the players most of the time, the technology enables accurate positioning of the ball. SmartBall can differentiate between who has possession from who is simply near the ball or contesting possession. The micro-technology within the Sherrin weighs only 5g. Since Sherrin footballs are made from leather, a natural material, ball weight typically varies by 40-50 grams so the inclusion of the e-tag is negligible. Shaun Holthouse, Catapult CEO, said this technology helped to tie the physical and tactical aspects of the
SWEATING SCIENTIFICALLY: Bombers Brent Stanton (left) and Scott Welsh. game together for coaching staff. “A player may have put in a lot of effort in terms of total distance and may have played at a high intensity but that doesn’t necessarily mean they have had a good effect on the game,” he said. “The ball tracking enables a coach to tie in the physical effort of players and tactical aspects of the game where you can see that a full forward made, for example, 30 efforts, but contested the ball with 10 of those efforts and gained possession with five. “You can start looking at the efficiency
SmartBall analysis features Ball use graphic:
Zone defence graphic:
How a team is moving the ball over the field. Are they going through the corridor or on the wings? Are they getting held up at the 50m mark?
See the zone each defender is protecting. See holes in the zone
Wednesday, March 17, 2010
of physical effort.” SmartBall technology also allows coaches to analyse ball movement and possession chains with real-time tactical animations of play, as well as automatically measuring key stats like disposals in free or congested space. The technology will also be useful at training, enabling staff to monitor the possessions of each player and adjust their training load appropriately. The SmartBall was launched in November 2009 and is now being trialed at several AFL clubs.